The Center for Archaeological Studies (CAS) 2014 excavations at the Spring Lake Site (41HY160) recovered more than 6,000 fragments of animal bone. Detailed analysis of the bone, often termed faunal analysis, began in the summer of 2016. Faunal analysis is part of a specialty in archaeology that is known as zooarchaeology (Reitz and Wing 2008). The bone fragments were analyzed to identify the animals represented and human modification from subsistence or bone technology activities. Procedures began with sorting into groups based on size of animal, signs of burning, or obvious evidence of butchering, skinning, or technological modification (Figure 1).

Fragments of animal bone recovered from the Spring Lake Site are small and in poor physical condition. The faunal analysis required techniques I’ve used over the past 20 years (Figures 2 and 3). Special lighting includes an overhead general light and a low sidelight that increases contrast. The sidelight reveals changes to the bone surface. Carnivore damage and root-etching modify the bone surface. Butchering damage and technological modifications made during tool or ornament manufacture and use each leave distinctive traces on the surface of bone.

Many small fragments were identifiable as skeletal elements from specific animals, often to genera or species used in biological classification. With standard zooarchaeological procedures, skeletal materials from reference specimens of fish, birds, and mammals were used to identify the faunal material. Some of the reference specimens were loaned from the Vertebrate Paleontology Laboratory at the University of Texas at Austin. Deer and bison reference specimens belonging to CAS were also used. Fish and squirrel specimens came from my own reference collection (Figures 4 – 7). Historical records of fish documented in the region by Kenneth Jurgens (1951) were also used in determining what species might be identified during the analysis, as well as other published references containing detailed anatomical drawings (Figure 8).

Figure 8: Anatomical drawing of rabbit rear foot from published reference used during faunal analysis.

Many fragments showed signs of butchering or cooking by the site’s inhabitants. Skinning and butchering leave distinctive cutmarks. Direct heat cooking, such as grilling or roasting, leaves distinctive discoloration of bone fragments. Some fragments were completely discolored by heat from inclusion in the soil surrounding earth ovens used to bake plants. Other fragments were incinerated by heat over 850o F that removed most organic material from the bone.

Some fragments retained signs of specific modification made during manufacture and use of bone tools and ornaments. Bone tools often exhibit scrape marks made to remove the periosteum layer from the bone surface; distinctive grooves cut to allow controlled snapping of the bone into segments; grinding of edges; and wear left by contact with plant materials, hides, or other substances when used by the site’s inhabitants. Incised bone artifacts and bone beads represent ancient artistic expression and allow us to study behavior beyond subsistence (Figure 9).

Assignment of bone fragments to the most appropriate taxonomic group requires an understanding of bone structure and skeletal anatomy of all potential animal groups, from fish and reptiles to birds and mammals. Some of the bones are easy to identify, based on their structure and morphology (Figure 10 and Figure 11). Distinctive features allow identification of bone fragments to specific animal form and skeletal element.

One bone tool fragment (Figure 14) shows clear signs of grooving and snapping used to detach bone tool blanks from large mammal long bones during manufacture. The irregular edges remaining from blank detachment may indicate that the tool was broken before being completed.

The same process was used to make both formal and informal tools. Figure 15 shows an informal hide-working tool fragment that retains grooving, but also helical fracturing. Figure 16 is part of a formal tool used in processing silica-rich plants.

Figure 15: Fragment of informal bone tool from Spring Lake Data Recovery Project with grooving used to detach tool blank from deer or antelope long bone. Narrow end has use wear from hide working.Figure 16: Fragment of Early Archaic bone tool from Spring Lake Data Recovery Project with manufacturing evidence and use-wear from silica-rich plants.

Much of my recent research has focused on fauna from sites in the Lower Pecos region of West Texas (Castaneda, et al. 2016; Jurgens 2005a, 2005b, 2006, 2008, 2014a, 2014b, 2015; Jurgens and Rush 2015). During the Spring Lake Data Recovery Project faunal analysis, I’ve noticed many similarities to the Lower Pecos study results. Bone tool or ornament fragments, and evidence for their manufacture, have rarely been documented in Central Texas. Analysis of the Spring Lake faunal material is showing us that the same processes used to make the tools and ornaments in the Lower Pecos were in use in Central Texas by the Early Archaic. Sites such as Spring Lake help us open the doors onto the past to understand how widespread cultural processes, such as bone technology, were prevalent in prehistory.